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Salvatore Cisternino

Publications and source records attributed to Salvatore Cisternino.

11 recordsLinked to original sources

Stability of levamisole oral solutions prepared from tablets and powder.

PURPOSE: To study the stability of levamisole oral solutions (25 mg/mL) prepared from powder and tablets stored at 4 +/- 3 degrees C and 23 +/- 2 degrees C in amber glass prescription bottles. METHODS: Levamisole 25 mg/mL solutions were prepared from commercially available 50-mg tablets or from pure powder in sterile water. Levamisole concentrations were determined in duplicate by a stability-indicating HPLC method at 0, 1, 2, 3, 4, 7, 14, 30, 60 and 90 days. The initial and final pHs of solutions were measured. RESULTS: The recovery of levamisole from tablets was 100 +/- 2.1%. No color or odour changes were observed during the study period. The oral solutions prepared from powder were stable at least 90 days stored at 4 and 23 degrees C. The oral solutions prepared from tablets were stable at least 90 days at 4 degrees C and 15 days when stored at 23 degrees C. The initial pH of solutions prepared from powder and tablets were 5.30 and 4.55, respectively. Initial and final pH values were significantly different (p<0.001) for the two solutions. CONCLUSIONS: Levamisole 25 mg/mL oral solutions can be prepared from tablets or powder with sterile water for irrigation and stored for 90 days under refrigeration, taking account of the lack of microbiological contamination.

Administration, Oral↗

Stability of bortezomib 1-mg/mL solution in plastic syringe and glass vial.

BACKGROUND: The proteasome inhibitor bortezomib (BTZ), used in antineoplastic chemotherapy, must be diluted in NaCl 0.9% for injection and stored for no more than 3 hours in a syringe or 8 hours in a vial. Better information on its stability could improve storage. OBJECTIVE: To assess the stability of BTZ solution (1 mg/mL) in syringes and vials. METHODS: BTZ 1-mg/mL solutions were prepared by adding sterile NaCl 0.9% to Velcade vials containing 3.5 mg of lyophilized BTZ. Syringes were filled with 1 mL of solution and stored in the dark at 5 degrees C or 60 degrees C; others were not protected from light and stored at 22 degrees C. Velcade vials containing 1 mL of solution were stored at 5 degrees C in the dark. Samples were taken at various times over 23 days and assayed in duplicate. An HPLC method for assaying the stability of BTZ was validated. Appearance and pH were recorded. RESULTS: There was no color change or precipitation in the samples, and the pH was stable. Oxidation, light, and storage temperature all affected the chemical stability of BTZ. The mean concentrations of BTZ in syringes stored for 2, 3, and 5 days at 60, 22, and 5 degrees C were >95% of the initial concentration. The mean concentration of BTZ in vials stored for 5 days at 5 degrees C was >95% of the initial concentration. CONCLUSIONS: BTZ stored refrigerated in vials or syringes and protected from light is chemically stable for 5 days after reconstitution.

Antineoplastic Agents↗

Structure-activity relationships in platelet-activating factor. 12. Synthesis and biological evaluation of platelet-activating factor antagonists with anti-HIV-1 activity.

The HIV-1 central nervous system infection leads to the onset of neurological impairments called AIDS dementia complex (ADC). PAF plays an important role in this pathology, as it is an HIV-1-induced neurotoxin produced by infected or activated macrophages and microglia, in the brain. We previously reported that PAF-antagonists bearing a trisubstituted piperazine presented in vitro anti-HIV-1 activity in human macrophages. To improve the pharmacological activities of our lead compound, 1a, we modified its carbamate function and evaluated both its antiretroviral and anti-PAF activities. One carbamate derivative (10c) demonstrated a similar antiviral activity but a higher anti-PAF potency, whereas 4a, with an ureide function, presents an increased antiviral activity and can be considered as a pure antiretroviral drug, as it does not present PAF-antagonism. Moreover, we measured the ability of 1a to cross the blood-brain barrier, using the in situ mouse brain perfusion method and its plasmatic concentrations after iv and po administration. The transport parameter measured (K(in)) proves that 1a is able to cross this biological barrier, but a pharmacokinetic study reveals its weak bioavailability in rats.

Animals↗

Expression, up-regulation, and transport activity of the multidrug-resistance protein Abcg2 at the mouse blood-brain barrier.

The breast cancer resistance protein (BCRP/ABCG2) is, like P-glycoprotein (P-gp), a member of the ABC family of drug transporters. These proteins actively transport various anticancer drugs from cells, causing multidrug resistance. The physiological expression of P-gp/ABCB1 at the blood-brain barrier (BBB) effectively restricts the brain uptake of many antitumor drugs by mediating their active efflux from the brain to the blood vessel lumen. However, little is known about the function of Abcg2 at the BBB in vivo. We used in situ brain perfusion to measure the uptake of two known Abcg2 substrates, prazosin and mitoxantrone, and the nonsubstrate vinblastine by the brains of wild-type and P-gp-deficient mutant mdr1a(-/-) mice with or without the P-gp/Abcg2 inhibitor GF120918 or the P-gp inhibitor PSC833. P-gp had no effect on the brain transport of prazosin and mitoxantrone at the mouse BBB, but wild-type and P-gp-deficient mouse brains perfused with GF120918 or a high concentration of prazosin showed carrier-mediated effluxes of prazosin and mitoxantrone from the brain that did not involve P-gp. In contrast, the brain uptake of vinblastine was restricted only by P-gp and not by Abcg2 at the BBB. The amounts of abcg2 mRNA in cortex homogenates and capillary-enriched fractions of wild-type and mdr1a(-/-) mouse brains were measured by real-time quantitative reverse transcription-PCR. There was approximately 700-times more abcg2 mRNA in brain microvessels than in the cortex of the wild-type mice, confirming that Abcg2 plays an important role at the BBB. There was also approximately 3 times more abcg2 mRNA in the microvessels from P-gp-deficient mutant mouse brains than in the microvessels of wild-type mouse brains. These findings confirm that Abcg2 is a physiological transporter at the BBB that restricts the permeability of the brain to its substrates in vivo. Lastly, the defective P-gp in the mutant mdr1a(-/-) mice was associated with increased abcg2 mRNA at the BBB and a greater export of prazosin and mitoxantrone from the brain, as measured in the P-gp-deficient mice versus the wild-type mice.

ATP Binding Cassette Transporter, Subfamily B↗

In situ transport of vinblastine and selected P-glycoprotein substrates: implications for drug-drug interactions at the mouse blood-brain barrier.

PURPOSE: To study the intrinsic parameters of P-glycoprotein (P-gp) transport and drug-drug interactions at the blood-brain barrier (BBB), as few quantitative in vivo data are available. These parameters could be invaluable for comparing models and predicting the in vivo implications of in vitro studies. METHODS: The brains of P-gp-deficient mice mdr1a(-/-) and wild-type mice were perfused in situ using a wide range of colchicine, morphine, and vinblastine concentrations. The difference between the uptake by the wild-type and P-gp-deficient mice gave the P-gp-linked apparent transport at the BBB. Drug-drug interactions were examined using vinblastine and compounds that bind to P-gp sites (verapamil, progesterone, PSC833) other than the vinblastine site to take into account the multispecific drug P-gp recognition. RESULTS: P-gp limited the brain uptake of morphine and colchicine in a concentration-independent way up to 2 mM. In contrast, vinblastine inhibited its own P-gp transport with an IC50 of approximately 56 microM and a Hill coefficient of approximately 4. The vinblastine efflux by P-gp was described by a Km at 16 microM and a maximal efflux velocity, Jmax, of approximately 8 pmol s(-1) g(-1) of brain. Similarly, vinblastine brain transport was increased by inhibiting P-gp as shown by the IC50 ranking, which was PSC833 < verapamil < vinblastine < progesterone. CONCLUSIONS: P-gp is responsible for both capacity-limited and -unlimited transport of P-gp substrates at the mouse BBB. In situ perfusion of mdr1a(-/-) and wild-type mouse brains could be used to predict drug-drug interactions for P-gp at the mouse BBB.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Peptide-vector strategy bypasses P-glycoprotein efflux, and enhances brain transport and solubility of paclitaxel.

We present the results obtained with paclitaxel coupled to a peptide-vector SynB3 (PAX-OSUC-SynB3), showing that this peptide-vector enhances the solubility of paclitaxel and its brain uptake in mice using the in situ brain perfusion model. We also show by the in situ brain perfusion in P-glycoprotein (P-gp)-deficient and wild-type mice that vectorized paclitaxel bypasses the P-gp present at the luminal side of the blood-brain barrier. The effect of the vectorized paclitaxel on various cancer cells was not significantly different from that of free paclitaxel. These results indicate that vectorization of paclitaxel may have significant potential for the treatment of brain tumors.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Apparent lack of Mrp1-mediated efflux at the luminal side of mouse blood-brain barrier endothelial cells.

PURPOSE: The purpose of this work was to determine mrpl-mediated efflux across the luminal membrane of endothelial cells at the blood-brain barrier (BBB) in mice. METHODS: The transport of radiolabeled etoposide, 17beta-estradiol-D-17beta-glucuronide (E217betaG), vincristine, and doxorubicin across the BBB of mrp1(-/-) and wild-type mice was evaluated by in situ brain perfusion. Etoposide transport was also determined in P-glycoprotein-deficient mdr1a(-/-) mice perfused with both etoposide and mrpl inhibitors like probenecid or MK571. Cerebral vascular volume was determined by co-perfusion with labeled sucrose. RESULTS: Sucrose perfusion indicated that the vascular space was close to normal in all the studies, indicating that the BBB remained intact. The transport of etoposide, E217betaG, vincristine, and doxorubicin into the brain was not affected by the lack of mrp1. Trans-efflux studies in mrp1-deficient mice with etoposide and E217betaG confirmed that mrpl was not involved in the efflux of these substrates across the BBB. There was also a significant P-gp-mediated efflux of etoposide in studies with P-glycoprotein-deficient mdr1a(-/-) mice. Perfusion of mdr1a(-/-) mice etoposide plus probenecid or MK571 did not affect the brain transport of etoposide. CONCLUSION: Efflux mediated by mrp1 does not seem to occur across the luminal membrane of the endothelial cells forming the mouse BBB.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

In vivo saturation of the transport of vinblastine and colchicine by P-glycoprotein at the rat blood-brain barrier.

PURPOSE: To determine concentration-dependent P-gp-mediated efflux across the luminal membrane of endothelial cells at the blood-brain barrier (BBB) in rats. METHODS: The transport of radiolabeled colchicine and vinblastine across the rat BBB was measured with or without PSC833, a well known P-gp inhibitor, and within a wide range of colchicine and vinblastine concentration by an in situ brain perfusion. Thus, the difference of brain transport achieved with or without PSC833 gives the P-gp-mediated efflux component of the compound transported through the rat BBB. Cerebral vascular volume was determined by coperfusion with labeled sucrose in all experiments. RESULTS: Sucrose perfusion indicated that the vascular space was close to normal in all the studies, indicating that the BBB remained intact. P-gp limited the uptake of both colchicine and vinblastine, but the compounds differ in that vinblastine inhibited its own transport. Vinblastine transport was well fitted by a Hill equation giving IC50 at approximately 71 microM, a Hill coefficient (n) approximately 2, and a maximal efflux velocity Jmax of approximately 9 pmol s(-1) g(-1) of brain. CONCLUSIONS: P-gp at the rat BBB may carry out both capacity-limited and capacity-unlimited transport, depending on the substrate, with pharmacotoxicologic significance for drug brain disposition and risk of drug-drug interactions.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Nonlinear accumulation in the brain of the new taxoid TXD258 following saturation of P-glycoprotein at the blood-brain barrier in mice and rats.

1. TXD258, a new taxoid antitumor agent, is a poor substrate for the P-glycoprotein (P-gp) in Caco-2 cells. In this study, we investigated the amount of drug accumulating in the brains of rats and mice under a variety of conditions (dose and infusion time, species and plasma concentration) using conventional in vivo pharmacokinetic techniques and in situ brain perfusion. 2. Mice were infused with radiolabeled TXD258 at 15, 30, 45 and 90 mg m(-2) for 45 s or 1 h and rats were infused with 15 and 60 mg m(-2) over 2.3 min. The radioactivity in the plasma and brains was measured. The brain concentrations of TXD258 in mice and rats were maximal from 2 min to 1 h postinfusion and radioactivity was still detectable at 168 h. While the plasma concentration of TXD258 increased linearly in mice with the infused dose, the brain content increased more than proportionally with the dose between 15 and 90 mg m(-2). This nonlinear uptake of TXD258 also occurred in the plasma and brain of the rat. 3. These findings suggest that the protein-mediated efflux across the blood-brain barrier (BBB) becomes saturated. In situ brain perfusion studies confirmed that TXD258 is a P-gp substrate at the BBB of mice and rats. The P-gp of both species was saturated at the half-inhibitory concentration ( approximately 13 micro M) produced by i.v. infusion. 4 Thus, the observed nonlinear accumulation of TXD258 in the brain seems to occur by saturation of the P-gp at the rodent BBB. This saturation could have several advantages, such as overcoming a P-gp-mediated efflux, but the nonlinear pharmacokinetics could increase the risk of toxicity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Evidence for an active transport of morphine-6-beta-d-glucuronide but not P-glycoprotein-mediated at the blood-brain barrier.

Morphine-6-beta-d-glucuronide (M6G) is an active metabolite of morphine with high analgesic potency despite a low blood-brain barrier (BBB) permeability. The aim of the study was to elucidate its transport mechanism across the BBB. We first checked if M6G was effluxed by the P-glycoprotein (P-gp), as previously reported by others. Second, we investigated the role of anionic transporters like the multidrug resistance-associated protein mrp1 and the glucose transporter GLUT-1. The brain uptake of [14C]M6G was measured by the in situ brain perfusion technique in wild-type and deficient mice [mdr1a(-/-) and mrp1(-/-)], with and without probenecid, digoxin, PSC833 or d-glucose. No difference was found between P-gp and mrp1 competent and deficient mice. The brain uptake of [14C]M6G co-perfused with probenecid in wild-type mice was not significantly different from that found in group perfused with [14C]M6G alone. The co-perfusion of [14C]M6G with digoxin or PSC833 was responsible of a threefold decrease of its uptake in mdr1a competent and deficient mice, suggesting that another transporter than P-gp and sensitive to digoxin and PSC833, may be involved. The co-perfusion of [14C]M6G with d-glucose revealed a threefold decrease in M6G uptake. In conclusion, P-gp and mrp1 are not involved in the transport of M6G at the BBB level in contrast to GLUT-1 and a digoxin-sensitive transporter (probably oatp2), which can actively transport M6G but with a weak capacity.

ATP Binding Cassette Transporter, Subfamily B↗